Eye series • EDUCATION Pupil disorder Eye series – 19 Chris Hodge, BAppSc, DOBA, is Research Director, The Eye Institute, Chatswood, New South Wales. Jeff Friedrich, MBBS, FRANZCO, FRACS, is an Ophthalmic Surgeon, The Eye Institute, Chatswood, New South Wales. Case history FEEDBACK A 32 year old woman presents to the practice with a history of migraine. Answer 1 After a recent acute attack, the patient noticed that her right pupil was smaller Differential diagnoses may include the fol- than the left, being more noticeable in dim conditions. On the same side as lowing: the smaller pupil, the eyelid appears to • direct ocular trauma may lead to an irregu- have drooped slightly. She also notes lar pupil shape or function that her forehead feels hot and flushed. • pharmacological side effects may lead to There has been no change over the pupil dilation or constriction. Unless past week. topical, the effect is usually bilateral • complete third nerve palsy will result in a Figure 1. Horner’s syndrome Question 1 fixed and dilated pupil in the affected eye. List the differential diagnoses. Marked ptosis is usually present, which may mask a pupil defect. Concurrent affected pupil to remain dilated. The pupil Question 2 extraocular muscle palsies will lead to reacts poorly to light and this may Detail the sympathetic pathway to the motility disorders and diplopia. Third nerve increase the apparent difference between eye. palsies may also be pupil sparing. Causes pupil sizes. A near reflex is usually Question 3 may include vascular conditions (eg. present, although this may be reduced. aneurism), tumours and diabetes Re-dilation of the pupil will also be slower What conditions may lead to Horner’s • Horner’s syndrome (Figure 1) is caused by in the affected pupil. Reduced or loss of syndrome? an interruption of the sympathetic accommodation may occur and the Question 4 pathway to the eye. A common triad of patient may complain of blurred vision What examination features, in particular symptoms are seen: with near work which may resolve over of the pupil, would you look for in this – miosis of the ipsilateral pupil time. Long term, the affected pupil will patient? – a small to moderate ptosis in the upper constrict in size and remain fixed. Usually lid (and a corresponding elevation of the benign in origin, it typically affects women Question 5 lower lid [reverse ptosis]), and in their 30–40s. It may follow a viral illness Is it possible to localise the cause of the – anhydrosis of the ipsilateral side of • Argyll Robertson pupil defect usually pre- pupil defect through patient signs or the face. sents with small, irregular pupils that are symptoms? Both near and light pupil responses sluggish or nonresponsive to light, simi- Question 6 remain normal, however, there is usually a larly the pupils will dilate poorly with dim What is the prognosis? significantly slower dilation of the affected or pharmacologically induced conditions. pupil in dim conditions (dilation lag). The pupils will respond promptly to a near Horner’s syndrome may be caused by response (accommodation). Usually various conditions such as tumours, caused by neurosyphilis, trauma or migraine this condition is almost always bilateral • Adie’s tonic pupil defect will cause the in presentation. Reprinted from Australian Family Physician Vol. 33, No. 9, September 2004 729 Education: Pupil disorder Answer 2 rological examination looking for weakness onset facial or neck pain without a history of of limbs or sensory loss that may occur in trauma may indicate carotid artery dissec- The sympathetic pathway to the eye has three combination with the Horner’s syndrome. tion from pre-existing cardiovascular distinct sections. The first section (first order A controlled pupil examination will generally disease. Anhydrosis of the face and neck is neurons) originates in the hypothalamus. The provide the necessary information to clas- also suggestive of second order involve- fibres descend to the level of the eighth cervi- sify the defect. The practitioner should ment. cal and fourth thoracic vertebrae of the spinal begin with an examination of the eye for Third order or postganglionic lesions are cord where the fibres then synapse with local causes of the pupil irregularities such commonly vascular in origin and usually second order preganglionic fibres. as iris trauma or inflammation. occur in isolation of neurological deficits, Second order fibres pass over the apex of the The next step is to determine the response although the patient may suffer from facial lung and enter the superior cervical ganglion in to light and dark conditions. If the pupil dif- pain or ear, nose and throat disease. the neck synapsing with postganglionic fibres. ference (anisocoria) is greater in the dark, it Anhydrosis is generally limited to the ipsilat- These third order neurons travel via the inter- usually represents a dilation defect, ie. eral forehead. nal carotid artery and enter the eye through Argyll Robertson or Horner’s defect. If anis- the cavernous sinus. Fibres then branch to coria is greater in light conditions, a problem Answer 6 innervate the dilator muscle of the iris and with constriction is more likely, ie. Adie’s In the majority of cases, Horner’s syndrome the muscle of Mueller within the eyelid tonic pupil. To further differentiate these is permanent, although transient episodes (responsible for initiating eyelid retraction conditions the response to near stimulus is may be seen in cases following cluster during eyelid opening). Travelling via the necessary. Adie’s pupil will react sluggishly migraine attacks. Rate of resolution of the external carotid artery the postganglionic to a near stimulus. If there is no response to syndrome, if it does occur, may vary consid- fibres also serve to innervate the sweat either light or near conditions, a third nerve erably. The main goal is to detect and treat glands of the face. lesion or pharmacological condition may the underlying cause. Recognising the pres- exist. ence of Horner’s syndrome and immediate Answer 3 A ‘swinging flashlight’ test is used to detect referral to an appropriate specialist is para- Interruption of the pathway at any point a relative afferent defect of the optic nerve. mount to the patient’s health. along the sympathetic pathway will lead to Each pupil is stimulated with light in quick AFP the classic Horner’s triumvirate of symp- succession. The abnormal pupil will dilate Conflict of interest: none declared. toms: miosis, mild ptosis and anhydrosis. instead of constricting when stimulated. Conditions leading to Horner’s syndrome This is because the corresponding action of include: dilation of the normal eye (when the light Correspondence • trauma to the head or neck region (includ- source is removed) will be stronger than the Email: [email protected] ing surgical trauma) constriction effect caused by the light in • aneurysms of the aorta or carotid arteries front of the affected eye. • vascular disease (eg. brain stem stroke) • demylination disorders (eg. multiple Answer 5 sclerosis) In many cases the astute observer will be • malignancy of the lungs (eg. Pancoast’s able to localise the cause of Horner’s syn- tumour) and neck regions (eg. Hodgkin drome by the patient’s clinical signs. Gross The 5 domains of general practice disease). neurological deficits such as hemiparesis or 1. Communication skills and the A careful history and examination is required analgesia, dysarthria, ataxia and loss of patient-doctor relationship to establish the underlying cause of disease sweating of the entire half of the body com- 2. Applied professional in a patient with Horner’s syndrome. bined with Horner’s pupillary defects may knowledge and skills indicate lesions of the first order neurons. Answer 4 Second order neuron lesions are commonly 3. Population health and the Comparing the lid position of both eyes in associated with trauma to the chest and context of general practice primary position will provide evidence of neck. The patient may complain of facial, 4. Professional and ethical role ptosis. Look for an area of dry, hot skin neck or chest pain. This may also result along the ipsilateral facial and/or neck region from compression of the fibres due to an 5. Organisational and legal (reduced innervation of the sweat glands apical lung tumour (Pancoast’s tumour). dimensions with Horner’s syndrome) and perform a neu- Horner’s syndrome in the presence of acute 730Reprinted from Australian Family Physician Vol. 33, No. 9, September 2004.